a = "aabbdd"
b = "aabbdd"
print(a is b)
print(a == b)
print(id(a))
print(id(b))

print(a is not b)
print(a != b)
print("cc" in a)


e ="sxt100".isalnum() #检查字符串是否只包含字母和数字字符
c ="setshanxuetang".isalpha()#检查字符串是否只包含字母字符
d = "100".isdigit()#检查字符串是否只包含数字字符
print(e,c,d)